269 lines
7.5 KiB
C
269 lines
7.5 KiB
C
/*
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* net/dccp/minisocks.c
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*
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* An implementation of the DCCP protocol
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/dccp.h>
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#include <linux/skbuff.h>
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#include <linux/timer.h>
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#include <net/sock.h>
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#include <net/xfrm.h>
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#include <net/inet_timewait_sock.h>
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#include "ackvec.h"
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#include "ccid.h"
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#include "dccp.h"
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struct inet_timewait_death_row dccp_death_row = {
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.sysctl_max_tw_buckets = NR_FILE * 2,
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.period = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
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.death_lock = SPIN_LOCK_UNLOCKED,
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.hashinfo = &dccp_hashinfo,
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.tw_timer = TIMER_INITIALIZER(inet_twdr_hangman, 0,
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(unsigned long)&dccp_death_row),
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.twkill_work = __WORK_INITIALIZER(dccp_death_row.twkill_work,
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inet_twdr_twkill_work,
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&dccp_death_row),
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/* Short-time timewait calendar */
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.twcal_hand = -1,
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.twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
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(unsigned long)&dccp_death_row),
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};
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void dccp_time_wait(struct sock *sk, int state, int timeo)
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{
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struct inet_timewait_sock *tw = NULL;
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if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
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tw = inet_twsk_alloc(sk, state);
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if (tw != NULL) {
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const struct inet_connection_sock *icsk = inet_csk(sk);
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const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
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/* Linkage updates. */
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__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
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/* Get the TIME_WAIT timeout firing. */
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if (timeo < rto)
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timeo = rto;
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tw->tw_timeout = DCCP_TIMEWAIT_LEN;
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if (state == DCCP_TIME_WAIT)
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timeo = DCCP_TIMEWAIT_LEN;
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inet_twsk_schedule(tw, &dccp_death_row, timeo,
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DCCP_TIMEWAIT_LEN);
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inet_twsk_put(tw);
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} else {
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/* Sorry, if we're out of memory, just CLOSE this
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* socket up. We've got bigger problems than
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* non-graceful socket closings.
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*/
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LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket "
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"table overflow\n");
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}
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dccp_done(sk);
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}
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struct sock *dccp_create_openreq_child(struct sock *sk,
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const struct request_sock *req,
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const struct sk_buff *skb)
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{
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/*
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* Step 3: Process LISTEN state
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*
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* // Generate a new socket and switch to that socket
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* Set S := new socket for this port pair
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*/
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struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
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if (newsk != NULL) {
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const struct dccp_request_sock *dreq = dccp_rsk(req);
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struct inet_connection_sock *newicsk = inet_csk(sk);
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struct dccp_sock *newdp = dccp_sk(newsk);
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newdp->dccps_role = DCCP_ROLE_SERVER;
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newdp->dccps_hc_rx_ackvec = NULL;
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newdp->dccps_service_list = NULL;
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newdp->dccps_service = dreq->dreq_service;
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newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
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do_gettimeofday(&newdp->dccps_epoch);
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if (newdp->dccps_options.dccpo_send_ack_vector) {
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newdp->dccps_hc_rx_ackvec =
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dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
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GFP_ATOMIC);
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/*
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* XXX: We're using the same CCIDs set on the parent,
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* i.e. sk_clone copied the master sock and left the
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* CCID pointers for this child, that is why we do the
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* __ccid_get calls.
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*/
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if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
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goto out_free;
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}
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if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid,
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newsk) != 0 ||
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ccid_hc_tx_init(newdp->dccps_hc_tx_ccid,
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newsk) != 0)) {
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dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
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ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk);
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ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk);
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out_free:
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/* It is still raw copy of parent, so invalidate
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* destructor and make plain sk_free() */
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newsk->sk_destruct = NULL;
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sk_free(newsk);
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return NULL;
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}
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__ccid_get(newdp->dccps_hc_rx_ccid);
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__ccid_get(newdp->dccps_hc_tx_ccid);
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/*
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* Step 3: Process LISTEN state
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*
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* Choose S.ISS (initial seqno) or set from Init Cookie
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* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
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* Cookie
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*/
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/* See dccp_v4_conn_request */
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newdp->dccps_options.dccpo_sequence_window = req->rcv_wnd;
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newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
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dccp_update_gsr(newsk, dreq->dreq_isr);
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newdp->dccps_iss = dreq->dreq_iss;
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dccp_update_gss(newsk, dreq->dreq_iss);
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/*
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* SWL and AWL are initially adjusted so that they are not less than
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* the initial Sequence Numbers received and sent, respectively:
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* SWL := max(GSR + 1 - floor(W/4), ISR),
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* AWL := max(GSS - W' + 1, ISS).
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* These adjustments MUST be applied only at the beginning of the
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* connection.
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*/
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dccp_set_seqno(&newdp->dccps_swl,
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max48(newdp->dccps_swl, newdp->dccps_isr));
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dccp_set_seqno(&newdp->dccps_awl,
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max48(newdp->dccps_awl, newdp->dccps_iss));
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dccp_init_xmit_timers(newsk);
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DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
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}
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return newsk;
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}
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/*
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* Process an incoming packet for RESPOND sockets represented
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* as an request_sock.
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*/
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struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
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struct request_sock *req,
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struct request_sock **prev)
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{
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struct sock *child = NULL;
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/* Check for retransmitted REQUEST */
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if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
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if (after48(DCCP_SKB_CB(skb)->dccpd_seq,
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dccp_rsk(req)->dreq_isr)) {
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struct dccp_request_sock *dreq = dccp_rsk(req);
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dccp_pr_debug("Retransmitted REQUEST\n");
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/* Send another RESPONSE packet */
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dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1);
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dccp_set_seqno(&dreq->dreq_isr,
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DCCP_SKB_CB(skb)->dccpd_seq);
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req->rsk_ops->rtx_syn_ack(sk, req, NULL);
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}
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/* Network Duplicate, discard packet */
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return NULL;
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}
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DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
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if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
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dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
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goto drop;
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/* Invalid ACK */
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if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
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dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
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"dreq_iss=%llu\n",
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(unsigned long long)
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DCCP_SKB_CB(skb)->dccpd_ack_seq,
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(unsigned long long)
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dccp_rsk(req)->dreq_iss);
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goto drop;
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}
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child = dccp_v4_request_recv_sock(sk, skb, req, NULL);
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if (child == NULL)
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goto listen_overflow;
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/* FIXME: deal with options */
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inet_csk_reqsk_queue_unlink(sk, req, prev);
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inet_csk_reqsk_queue_removed(sk, req);
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inet_csk_reqsk_queue_add(sk, req, child);
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out:
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return child;
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listen_overflow:
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dccp_pr_debug("listen_overflow!\n");
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DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
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drop:
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if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
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req->rsk_ops->send_reset(skb);
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inet_csk_reqsk_queue_drop(sk, req, prev);
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goto out;
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}
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/*
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* Queue segment on the new socket if the new socket is active,
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* otherwise we just shortcircuit this and continue with
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* the new socket.
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*/
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int dccp_child_process(struct sock *parent, struct sock *child,
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struct sk_buff *skb)
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{
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int ret = 0;
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const int state = child->sk_state;
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if (!sock_owned_by_user(child)) {
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ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
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skb->len);
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/* Wakeup parent, send SIGIO */
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if (state == DCCP_RESPOND && child->sk_state != state)
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parent->sk_data_ready(parent, 0);
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} else {
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/* Alas, it is possible again, because we do lookup
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* in main socket hash table and lock on listening
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* socket does not protect us more.
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*/
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sk_add_backlog(child, skb);
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}
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bh_unlock_sock(child);
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sock_put(child);
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return ret;
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}
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